It is known that a cured epoxy resin obtained by curing an epoxy compound having mesogenic groups with the use of a curing agent such as a diamine compound exhibits liquid crystallinity (for example, see JP-A 9-118673). However, it is difficult to cure such an epoxy resin by melt blending at the curing temperature or below with the use of a curing agent such as diaminodiphenylmethane because of its high melting temperature.